2. Description of Prior Art
Regulating the milieu interne, the autonomic nervous system plays an important role in human health and general condition. Routed in the hypothalamic portion of the diencephalon, peripherally it is distinct in its two divisions: sympathetic and parasympathetic. Most visceral structures receive both sympathetic and parasympathetic innervation. The two divisions of the autonomic nervous system principally act antagonistically; the delicate balance between them regulates many visceral functions.
Dysfunction of the autonomic nervous system is related to many clinical disorders. Angina pectoris which ranks among the most frequent causes of death in the United States, appears to be intimately related to excessive vasoconstriction of the coronary arteries and to a resulting ischemia of the hearth muscles. Peptic ulcer, another common affliction of modern man, is related to an over-secretion of hydrochloric acid and abnormal gastric activity.
Up to now, the functional state of the autonomic nervous system could be estimated only roughly through a qualitative evaluation of some existing dysfunction caused by an imbalance between the two divisions of the system:
An increased parasympathetic functioning can be noticed by a pupillary constriction, and accommodation of optic muscles; by increased secretion of the submaxillary, sublingual, and lacrimal glands; by inhibition of cardiac functions and coronary vasoconstriction; by constriction of bronchial musculature; by increased peristalsis of the digestive tract and increased secretion of hydrochloric acid in the stomach; by inhibition of anal and vesical (urinary) sphincter muscles; by vasodilatation of cutaneous vessels.
Respectively, an excitation of sympathetic functions results in dilatation of the pupils, increase in salivary and lacrimal gland secretions, an acceleration of cardiac activity and coronary vasodilatation, dilatation of the bronchi, inhibition of peristalsis and vasoconstriction of intestinal blood vessels, contraction of anal and internal (renal) sphincters, vasoconstriction, excitation of pilomotor muscles, and secretion of sweet glands.
Consequently, there is neither an objective method for the quantitative measurement of the balance between the two divisions of the autonomic nervous system, nor one that assesses quantitatively the functional state of the system, including the level on which this balance appears.